How accessible are Borneo's national parks?

Hi all! My girlfriend and I are planning to visit Indonesia later this year and wanted a chunk of our trip to include Borneo. I'm having a lot of trouble finding any in-depth info about the interiors of their parks, specifically Betung Kerihun. I was hoping to go hiking in the rainforest somewhere, just a day hike at the most, no backpacking or overnight stays. I don't know if they just don't have trails or if I'm looking in the wrong spot. It also looks like waterways are their main method of transport into and out of the park? I can't tell if people mostly stay on the outskirts of the park or if it's common for people do get deeper into them somehow. Any info from those of you who've been here would be much appreciated.

Author: genericguy6